Method of and apparatus for cutting forms from stone slabs



' Sept. 29, 1931.

G. M. RAND 1,825,420

METHOD OF AND APPARATUS FOR CUTTING FORMS FROM STONE SLABS Filed March 11. 1927 l8 orge and ATTys.

Patented Sept. 29, 1931 PATEN T OFFICE GEoEGE M. RAND, E EAREE, VERMONT METHOD OF AND APPARATUS FOR currme roams rno vr s'roNE sLAEs Application filed March 11, 1927. Serial No. 174,484.

This invention relates to a method of cutting forms of different shapes from stone slabs and to a machine by which the method can be carried out and an object of the invention is to provide an improved method and apparatus by which forms of different shapes may be accurately and quickly cut from stone slabs without danger of breaking the stone.

In carrying out my improved method I employ two sharp-edged dies which are opposed to each other and each of which has a contour corresponding to that of the form or block to be cut from the stone slab.

The stone slab is placed between the dies and the dies are then pressed against the slab so that each die scores the face of the slab with which it has contact. One of the dies is thengiven 'a sharp blow which re- 2 sults in breaking the slab through from one score line to the other thus producing a block or form of the desired shape; By

means of this method blocks can be quickly and accurately cut from a stone slab and without danger of breaking either the slab or the form.

In order to give an understanding of my invention I have illustrated in the drawings a selected embodiment thereof which will now be described after which the novel features will be pointed out in the appended claims.

Fig. 1 is a perspective view of a machine embodying my invention;

Fig. 2 is an enlarged sectional view showing the action of the dies on the stone slab;

Fig. 3 is a perspective View of a form of block which has been cut from the slab by my improved machine.

Referring first to Fig. 2, 1 indicates a slab of stone from which it is desired to cut a block or form such for instance as indicated at 2 in Fig. 3. The block shown in Fig. 3 is circular in shape but the particular shape of the block is not important as with my invention a block of any desired shape may be cut from the stone slab 1.

As stated above the cutting is done by subjecting the opposite sides of the stone slab 1 to the action of two similar sharpedged dies which are pressed against the faces of the stone slab with sufficient pressure .to score the latter and then one of the dies is struck a blow which causes the stone to be fractured along a zone connecting the score lines.

In Fig. 2 the two dies are indicated at 3 and 4, each having a sharp edge 5 of the contour of theblock or form to be cut from the slab '1. In the illustrated embodiment where a circular block is to be cut the sharp edges 5 of each die will be circular. These two die members 3.and 4 are forced against the faces 6 and 7 of the stone 1 with sufficient pressure to score the faces and after this is done one-of the'dies is then given a sharp blow whichcauses the stone to frac- {ture aiong the-line 8 connecting the two I scorelines thus cutting a circular block from lthe slab 1. Q I So far as the method is concerned the .dies 3 and 4 maybe mounted in any ap- {proved waybut I have shown in Fig. 1 an lapparatus which may conveniently be used for practising my improved method. In said figure the dies 3 and tare supported on a frame 9 which is provided with a bed {10 on which the lowerdie 4: is mounted and is also provided with ahead 11' carrying a plunger 12 on the lower end of which the die 3 is secured. This plungeris movable vertically through bearings 13 on the head 11 and may be given its vertical movement in any desired way. Merely'for illustrative purposes I have shown the plunger as having rack teeth 14 thereon which mesh with a pinion 15, the latter having the head 16 integral therewith from which extend the handles or arms 17 by which the pinion may be turned and the die 3 raised and lowered.

I will preferably so mount the die 4 that it will be self-adjusting, that is, it is so supported that when pressure is applied thereto it will automatically adjust itself to bring the plane of the cutting edge 5 thereof parallel and coincidentfwith the plane of the face 7' of the stone, This lower die 4 is shown as carried by a holder 18 having concave under face 19 which rests on andfits against the convex upper face 20 of a bolwithout danger of cracking or breaking ster member 21. This member 21 is in turn supported on the bed 10.

The holder 18 is shown as having an annular flange 22 through which extends a plurality of studs 23 that are screwed into the bolster member 21. Each stud 23 has a spring 25 thereon between the flange 22 and the bolster plate and another spring 25 between the flange 22 and a collar 26 on the stud. These springs thus act as centering springs and normally retain the holder 18 in its true vertical position but they permit the holder 18 and the die 4 to have a slight rocking movement. r

In case the two faces 6 and 7 of the stone slab 1 are not quite parallel the lower die member will automatically adjust itself when pressure is applied so that the plane of the cutting edge 5 thereof will come into coincidence with the plane of the lower face 7 of the stone whereby the cutting edge 5 will be pressed against the stone face 7 uniformly throughout its extent.

In cutting a block or form such as indicated at 2 in Fig. 3 from a stone slab 1 the latter is placed between the dies and the plunger 12 is lowered against the slab and then pressure is applied to the slab through the dies to cause the sharp edges 5 thereof to score the faces 6 and 7 of the slab. lhereafter, the upper end 27 of the plunger 12 is given a sharp blow with a hammer, which blow is transmitted through the plunger .to the die 3. he result of the sharp blow is to fracture the stone slab 1 along the line 8 connecting the two score lines thus cutting the block 2 from the slab.

By this method it is possible to cut a block 2 as shown which has theexact contour of the sharp edges 5 of the dies and either the block or the slab. The operation of thus cutting a form from the slab can be accomplished very quickly and by means of unskilled help.

A block or form of any desired shape may be cut from a stone slab in accordance with this invention by merely selecting or using dies of the desired shape. While, therefore, I have for illustrative purposes shown dies having circular cuttingedges by which a circular block or form is produced yet the shape of the dies may be varied to produce a block of any form without depart- -.ing from the invention.

The method embodying the invention may also be used for cutting forms from slabs of different thicknesses depending on the use to which the blocks or forms are to be The invention is specially useful in cutting out samples to be used for showing the quality or characteristic of the stone.

A person investigating the qualities of granite or any similar stone desires to see how the stone will polish, the character of a sawed face of the stone and also the character of the so-called rock face or face where the stone has been broken.

A form or block produced according to my invention is specially useful in getting out samples because by means of it the block may exhibit these three kinds of faces. For instance, the slab '1 may have the upper face 6 polished and the lower face 7 a sawed face, in which case the form 2 which is cut from the slab will have its upper face 28 polished and its lower face 29 a sawed face while the edges will show the quality or characteristic of the rock or broken face.

I claim:

1. A machine for cutting forms from a stone slab, comprising a frame having a bed and a head provided with a bearing, a selfadjusting die carried by the bed, a plunger carried by the head and extending through said bearing, a second die carried by the plunger, and means to move vertically the plunger and the die carried thereby, the upper end of the plunger extending above the bearing and being provided with a head adapted to be struck a blow with a hammer.

2. The method of cutting forms from a stone slab which comprises pressing against opposite facesof the stone slab two opposed dies and applying to said dies a steady pressure suflicient to cause them to score the faces of the slab but insuflicient to cause them to crack the slab, and while the dies are still so pressed against the faces and after the latter have been scored striking one of the dies a hammer-like blow thereby to fracture the slab transversely from one score line to the other.

In testimony whereof, I have signed my name to this specification.

GEO. M. RAND. 

